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Despite our often silly demeanor, we take investing pretty seriously here at the Fool, and there can be no greater investment than one that makes this world a better place. That's why I'm proud of the Fool's yearly Foolanthropy drives, and this year's touches on a topic particularly important to me -- water security.

As my colleagues Alyce Lomax and Ilan Moscovitz explain in the Foolanthrophy 2012 announcement, hundreds of millions of people around the world lack access to reliable, clean water, costing them billions of wasted hours carrying it from far-off sources or suffering from illnesses brought on by unclean drinking water. It's a major issue, but one that has a solution. I ask you all to follow the preceding link to Alyce and Ilan's article and read about what you can do to help invest in a better future for millions.

Fortunately for the human side of things, water is not like most other commodities in that it can't be traded on a futures exchange somewhere, to have its cost bid up by speculators, nor is its supply tightly controlled by an OPEC-like cartel that can use it for political purposes. Unfortunately, that doesn't mean it's cheap and widely abundant, either.

Only about 2.5% of the world's water is fresh water, the sort that life needs, and less than 1% of that amount is available for use. Worse still, global demand for water is increasing as emerging markets become more developed, and specific areas of scarcity are growing as more people move to large cities. A recent report by the National Intelligence Council estimates that by 2030, global water requirements will be 40% higher than currently sustainable supplies, and more than half the world's population will live in areas with severe water stress.

How to investFortunately, there are companies dedicated to bringing more water to more people, while wasting less of it. Even in the developed world, water loss through old, leaky pipes can range from 30% to 50%, and in poorer regions of the world, water is often carried from the source, so a good deal of it is lost from splashing and from quenching the thirst of the tired person carrying it. Similarly, a massive amount of water is wasted all over the world with inefficient irrigation methods such as flood irrigation, which is essentially what it sounds like.

The need to carry water more efficiently, as well as replace existing infrastructure as increasing urbanization puts it under more strain, makes piping companies such as Flowserve a good opportunity. Flowserve is in a particularly good position among its peers because it gets almost half of its sales from developing areas like Asia, Africa, and Latin America.

Irrigation equipment manufacturers Lindsay and Valmont Industries provide equipment that is vastly more efficient than traditional irrigation methods, on the order of 90% compared with less than 50%. Much of the developing world still uses traditional methods, so Lindsay and Valmont have a strong opportunity to grow as they help these regions use their water more efficiently.

Using water more efficiently is only half the battle, however. Desalination and sanitization can increase supplies of drinkable water. Unfortunately, Consolidated Water is the only public desalination company, and it focuses purely on countries in the Caribbean, limiting its long-term growth opportunities. Calgon Carbon , however, is one of the world's largest manufacturers of water filtration and sanitization technology, deriving about half its revenue internationally and about 15% from emerging countries.

The Foolish bottom lineWater is sadly an increasingly scarce resource that too few people have reliable access to. Charities can go a long way to help, but these companies are well placed to provide better infrastructure and better technology to the areas that need it most. These are long-term opportunities, however, so I would recommend adding these companies to My Watchlist to stay up to date as they develop.

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